Manufacture of link parts for welded link chains



June 7, 1960 D A, sMn-H ETAL 2,939,272

MANUFACTURE OF LINK PARTS FOR WELDED LINK CHAINS Filed March 17, 1958 Inve tors r 9,, a a M Attorneys United States Patent .7 r n 2,939, MANUFACTURE OF LINK PARTS FOR WELDED if 'LINKCHAINS i. 1 Douglas A.'Smith, Hagley, and James A." Shirt, Brierley' Hill, England, assignors to SamuelTaylor & Sons (Bnerley l IilllLimited, Brlerley Hill, England 'Filed Mar. 17, 195s, Ser. No. 721,867 cum; priority, application Great llrltaln Apr. 10, 1951 V 2 Claims. cuss-3s This invention relates to the-manufacture of link parts for weldedlinkchains, the chief object being to provide an improvement in the manufacture of link parts for welded link chains of the kind in which each link has a central cross stud and the resistance or flash weld extends fully across the link in the axial plane of said stud. In this kind of welded link chain all the link parts are made alike, each such part comprising a U-shaped memher with integral stud portions projecting inwardly toward each other and into end-to-end abutment from the extremities of the two limbs.

'In the manufacture of chain link parts for welded link chains of the kind referred to, and according to the invention, an appropriate length of bar stock heated and bent upon itself to a U-shape is placed in a correspondingly shaped though longer tunnel afforded between separable parts of a forging die, the limbs of said tunnel being interconnected at an appropriate point distanced from the bend -by a cross tunnel also afforded between the die parts, and the extremities of the U-shaped workpiece in the die are operated upon by two equal-length plungers of a forging punch which enter and fill the ends of the U-shaped tunnel and, as the punch is advanced, upset the hot workpiece to ensure that it fills the U-shaped tlmnel throughout the length of the workpiece and to displace metal from the outer end portions of the limbs of said workpiece laterally inwardly into the cross tunnel so as to form stud portions which fill the cross tunnel, the end faces of the two plungers when the punch stroke is completed being in line with the outermost side of the cross tunnel.

The invention will now be more fully described with reference to the accompanying drawing; in which:

Fig. 1 shows a chain link with a central cross stud, said link comprising two similar U-shaped parts, each with its complements of the cross stud, secured together by a. resistance or flash weld extending fully across the link in the axial plane of said stud.

Figs. 2 and 3 are fragmentary views showing in side elevation and plan respectively a two-part forging die and associated forging punch with producing chain link parts.

Fig. 4 is a fragmentary front elevation of the closed forging die.

Fig. 5 is a fragmentary side elevation showing the forging punch at the end of its forging stroke and the completely forged link part in the die cavity in the parting face of the far-side die part, the nearside die part having been removed for the sake of clearness.

Referring to the drawing and particularly to Fig. 1, the welded chain link parts are alike and the resistance or flash weld joining them together is in the transverse centre plane A.B. Each U-shaped link part 10 as forged has integral stud portions 11 projecting inwardly toward each other into end-to-end abutment from the extremities of the two limbs (see Fig. 5). Flash or upset produced by welding is, of course, ground away or filed ofi.

Referring now particularly to Figs. 2 to 5 of .the draw- I ings, each link part 10 is made from an appropriate lengthg of bar stock heated and bent upon itself to form aU-I shaped workpiece or use '12 and then placed in a cor-. respondingly shaped though longer tunnel 13 'afiorded; by complementary cavities in the parting facesof the;

" separable parts 14, 15 of the forging die. A cross tunnel,

16 interconnects the limbs of the U-shaped tunnel13j at an appropriate point distanced from the bend, and the; outer end portions of said U-shaped tlmnel 13, between the. cross tunnel 16 and the front faces of the die parts.

i 14-, 15, are parallel and cylindrical to suit correspond ingly spaced cylindrical plungers 17 of the forging punch; 18, which plungers 17 are of equal length. inwar ly. beyond the cross tunnel 16 the tunnel '13 preferably in creases in cross-sectional area toward the centre of the .l' bend, said cross-section developing from circular man;

approximately oval shape at the bend with the major' axis of this oval section disposed longitudinally. Preferably the cross tunnel 16 has a semi-circular cross section with the flat side or diametrical face nearer to the front end faces of the die parts 14, :15 into which latter faces the ends of the tunnel 13 run out. The opposite semicircular side of the cross tunnel curves in the direction of the bend of the U-shaped tunnel so that the opposed ends of the cross tunnel on the bend side thereof are joined to the limbs by arcuate walls so as to afford one of the two openings on the opposite side of the stud of the completed link. Desirably this D-section cross tunnel 16 preferably also decreases in cross-sectional area toward the centre by being formed of a pair of straight walls which diverge from the center of the cross tunnel to the respective limbs of the U-shaped tunnel as shown.

The U-shaped workpiece or use 12 is made of bar stock of somewhat less diameter than that of the outer end portions of the limbs of the U-shaped tunnel 13, and its length is such that when the said U-shaped workpiece or use 12 is placed in the tunnel 13 its end portions project outwardly beyond the ends of the cross tunnel 16 as shown in Figs. 2 and 3.

After placing the U-shaped workpiece or use 12 in position and closing the die parts 14, 15 upon one. another, the forging punch 18 is operatedso that its plungers 17 enter and fill the ends of the U-shaped tunnel 13 and, as the punch 18 is advanced, said plungers 17 operate upon the ends of the hot workpiece or use 12 so as to upset the latter and cause it to fill said tunnel 13 and also to displace metal from the outer end portions of said workpiece or -use '12 laterally inwardly into the cross tunnel 16 to form the stud portions 11 until, finally, the latter abut end-to-end and fill the cross tunnel 16 and the end faces of the two plungers 17 are in register with the ends of the outermost or flat faces of the D-section cross tunnel.

With this arrangement the outer flat faces of the stud parts are contiguous with the end faces of the respective side limbs of the finished chain link part, and these transverse faces on two such link parts are resistance or flash welded to form a complete link, as shown in Fig. 1. It will, of course, be appreciated that, in building up a chain, inter-lacing of a link part with a previously welded link can be effected by opening up said link part, passing its one end through the vacant eye of the completed link and then closing said link part upon itself again before bringing the next link part into position for welding.

Having fully described our invention what we claim and desire to secure by Letters Patent is:

1. The manufacture of link parts for welded link chains of the kind referred to, which consists in heating an appropriate length of bar stock and bending it to a plain U-shape having a pair of parallel limbs of equal length; placing this U-shaped workpiece in a correspondingly shaped closed tunnel open only at the outer ends ofrthe lintb s thereof, said tunnel being afiorded between separable parts of a forging die which afiords also a cross tunnel interconnecting the limbs of the U-shaped tunnel inwardly of the outer ends thereof and at a point appropriately distanced from the bend, saicl cros's tunneli operating upon the extremities of the U'-sl1aped. work-t piece throughlthe open ends of said limbs by two equal-- lengthplungers of a forging punch which enter and" completely fill the ends of the U-shaped tunnel and advancing the punch so as to upset the hot workpiece to ensure that it fills the U-shaped tunnel throughout" the length of the workpiece and to displace metal from the outer end portionsof the limbs of sai'd workpiece lateral- 7 1y inwardly into the crosstunnel so as to form stud portions which fill the cross tunnel, the end faces of the two plungers when the punch stroke is completed being in line with the ends of the outermost side of the cross tunnel. 1 F

2. The manuiaeture of link parts for welded chains, as elainied in, 11,; wherein the flatside of ',said crosstunnel is formed of a pair of straight walls which divergetrom the center of,; said cross tunnel to the respective linibs of said, til-shaped tunnel.

References Cited in thefile of this, patent 'nm ran STATES r arenrs 1,939,735 Taylor .V--,.;,, Dec. 19, 1933 2,749,610 Welsch June 12, 1956 FQREIGN PATENTS B am; r b- 1. 9 

